1. Technical Field
The present invention relates to a liquid ejecting head provided with a piezoelectric element which causes a change in the pressure of pressure generating chambers communicating with nozzle openings and which has a piezoelectric layer and electrodes which apply a voltage to the piezoelectric layer, a liquid ejecting apparatus, and a piezoelectric element.
2. Related Art
Mentioned as the piezoelectric element is one in which a piezoelectric layer (piezoelectric film) containing a piezoelectric material which exhibits an electromechanical conversion function, e.g., a crystallized piezoelectric material, is sandwiched between two electrodes. Such a piezoelectric element is mounted as an actuator device of a bending vibration mode, for example, on a liquid ejecting head. Mentioned as a typical example of the liquid ejecting head is, for example, an ink jet recording head in which a part of pressure generating chambers communicating with nozzle openings which eject ink droplets is constituted by a diaphragm, and the diaphragm is transformed by a piezoelectric element to pressurize ink in the pressure generating chambers, whereby the ink is ejected from the nozzle openings in the form of ink droplets.
The piezoelectric material used as the piezoelectric layer constituting such a piezoelectric element has been required to have high piezoelectric properties, and lead zirconate titanate (PZT) is mentioned as a typical example thereof (Japanese Unexamined Patent Application Publication No. 2001-223404). However, a piezoelectric material in which the lead content is reduced has been demanded from the viewpoint of environmental problems. Mentioned as piezoelectric materials not containing lead are BiFeO3 piezoelectric materials containing Bi and Fe, for example. Mentioned as a specific example thereof are complex oxides represented as a mixed crystal of bismuth ferrate manganate, such as Bi(Fe,Mn)O3 and barium titanate, such as BaTiO3, (e.g., Japanese Unexamined Patent Application Publication No. 2009-252789).
Such a piezoelectric material containing the mixed crystal of bismuth ferrate manganate and barium titanate has a relatively small distortion. The distortion can be increased by applying a high voltage. However, when a high voltage is applied, there arises a problem that dielectric breakdown arises in some cases. Therefore, it has been required to prevent dielectric breakdown even when a high voltage is applied, i.e., to increase the withstand voltage. Moreover, in order to suppress the occurrence of cracking, the equalization of the crystal grain size has also been required. Such a problem is not limited to the liquid ejecting head typified by the ink jet recording head, and similarly arises in other piezoelectric elements.